1. Field of the Invention
The present invention relates to ink jet recording means in which a recording head unit for effecting recording by ink discharge and an ink tank unit containing ink to be supplied to said recording head unit are integrally constructed at use and in which said ink tank unit can be separated for replacement when necessary, and a packing therefor.
2. Related Background Art
Conventional ink jet recording apparatus is usually provided with a semi-permanently usable head (hereinafter called permanent head), and an ink cartridge which is interchangeably fitted on a device for ink supply to said permanent head through a tube extended in the recording apparatus. In such permanent head, however, the reliability of the recording apparatus is insufficient as it is difficult to completely avoid eventual failures such as nozzle blocking with dust or the time-dependent failures resulting for example from deterioration of the ink discharge element. and These has therefore been required a particular maintenance service system for maintaining recording performance.
On the other hand, for the purpose of improving reliability and cost reduction, there have been commercialized ink jet recording apparatus employing an interchangeable recording head cartridge (hereinafter called disposable head) in which an ink tank and a recording head are integrally constructed, thereby achieving the replacement of the recording head at a predetermined interval after using a predetermined ink amount.
However, a disposable head is higher in running cost than permanent head and has to be disposed of when the ink is used up even if the head still has sufficient performance. That is, since the usable amount of ink in such a disposable head cannot be made large for the purpose of securing the reliability and also in consideration of the size and weight of the disposable cartridge itself. In particular, the disposal of the head cartridge may have adverse ecological consequences which have caused stronger worldwide concern in recent years.
For this reason there has recently been proposed a cartridge configuration in which a recording head unit and an ink tank unit are rendered separable, said units being integrally united at the use but independently replaced when the ink is used up, thereby maintaining the advantage of the disposable head in terms of reliability while reducing running cost and giving consideration to ecological issues.
Such an ink cartridge, however, is associated with the drawback of evaporation of the ink filled in the ink tank, in the course of distribution, and there have been proposed configurations for preventing such ink evaporation in the ink tank, by forming the ink tank with metal or providing the ink tank with metal plating, as disclosed, for example, in the Japanese Patent Laid-Open Application No. 57-100088.
Also the recording head has been associated with a drawback of deterioration of the bubble generating property, giving rise to deteriorated print quality, resulting from contamination of the heater surfaces of the recording head by the ambient conditions, if the recording head is left without ink in the prolonged storage of the head or in the course of distribution.
Also, in such independently replaceable recording head and ink tank, the recording head has a limit in service life, beyond which the recording quality becomes deteriorated for example by the breakage of the heat generating resistors.
It is therefore extremely desirable to render the service life of the recording head easily understandable to the user.